• Korea-Australia Rheology Journal
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• 제17권2호
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• pp.87-95
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• 2005

In this study, we performed RTD measurement at the die exit of co-rotating twin-screw extruder using a non-destructive ultrasonic device. The ultrasonic device was attached at slit die and was composed of a steel buffer rod and 10 MHz longitudinal piezoelectric ultrasonic transducer. This in-line ultrasonic monitoring method is based on the ultrasonic response of $CaCO_3$ filled in polymer. The RTD is evaluated by variation of ultrasonic attenuation with time caused by change of the tracer concentration during extrusion. The ultrasonic tracer, pellet type of compounded $CaCO_3$ in polymer was used in this study. The effects of tracer concentration on RTD and flow patterns were studied. Evaluation for the residence functions at different screw speeds, feeding rates and screw configurations were also carried out.

• 한국식품조리과학회지
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• 제28권6호
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• pp.813-820
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• 2012

To develop the high quality gluten-free rice products with health functionality and desirable texture with moistness, the physicochemical properties of extruded rice flours prepared from the mixture of germinated brown and white rices were investigated. The domestic organic Samgwangbyeo was used to make white and germinated brown rices. White rice (WR) was dried after soaked for 6 h at $15{\pm}3^{\circ}C$ and mixed with germinated brown rice (GBR) with different mixing ratios (100:0, 75:25, 50:50, 25:75, 0:100). The operating conditions of twin screw extruder were 250 rpm of screw speed, $120^{\circ}C$ of barrel temperature, and 25% moisture content of rice flour. The ash, crude protein and crude lipid contents were significantly different (p<0.05) and those of extruded GBR were the highest values, but those of extruded WR were the lowest. The color difference of extruded WR based on white plate showed the lowest among them. The water binding capacity (334.16%), swelling power (8.83 g/g), solubility (33.13%), and total starch (79.50%) were the lowest in extruded GBR. The viscosities of all extruded rice flours by RVA were maintained during heating. The peak and total setback viscosities of extruded rice flours ranged 127-352 and 58.0-85.5 cP, respectively. The novel food biomaterial from germinated brown rice as well as white rice was developed by twin screw extruder. The extruded rice flours control the moistness to improve the texture and also have functional materials, dietary fiber, GABA, and ferulic acid, etc to increase quality of gluten free rice products.

• 한국가정과학회지
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• 제5권1호
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• pp.62-70
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• 2002

The objective of this study was to evaluate the effects of processing parameters of co-rotating twin screw extruder and dry methods on the level of resistant starch (RS) and the properties of extrudate prepared from normal maize starch. The processing parameters were used 90, 110, 130$^{\circ}C$ in temperature, 25.0~30.0% in moisture content, 150, 200, 250 rpm in screw speed and hot and cool air drying and drying after refrigerating in drying methods. The barrel temperature and drying methods had affected the level of resistant starch of extrudate. RS levels of extrudates were ranged from 2.4 to 15.5% by AOAC method. The extrudates, extruded at 110$^{\circ}C$ and then stored at 4$^{\circ}C$, showed the highest level of RS level (15.5%). Water absorption index increased with increasing moisture content and peak temperatures and viscosities of extudates decreased compare to that of raw starch from 94$^{\circ}C$ to 50~65$^{\circ}C$ and from 220 to 46~98 RVU, respectively. Extudates treated in 90$^{\circ}C$ and 110$^{\circ}C$ showed strong peak at $2{\theta}=6.7{\sim}17.0^{\circ}$ by X-ray diffractometry and had ~150$^{\circ}C$ endotherm like as that of RS3 starch by differential scanning calorimetry. In case of 130$^{\circ}C$, extrudates showed strong peak at $2{\theta}=20.0^{\circ}$ and had 106$^{\circ}C$ endotherm.

• 한국식품과학회지
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• 제23권1호
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• pp.81-87
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• 1991

15% 비율로 가수한 corn grit 원료를 reverse element 수를 달리한 스크류 조합을 사용한 실험실용 동방향 회전 이축 압출성형기로 extrusion cooking할 때, 각 스크류 조합에서 원료 투입량($30{\sim}60\;kg/hr$), 스크류 회전속도($200{\sim}400\;rpm$) 및 die hole 수($2{\sim}4$개) 등의 process parameters 변화에 대한 system parameters(압출온도 및 압력, 기계적 에너지 소모율 및 평균체류시간)의 변화 양상을 다중회기분산 분석을 통하여 분석하였다. 원료 투입량이 증가할 수록, 압출온도, 기계적 에너지 소모율 및 평균체류시간이 감소하는 경향을 보인 반면에 알출압력은 증가하였다. 그리고, 스크류 회전속도가 증가할 수록, 압출온도, 기계적 에너지 소모율 및 압출압력이 증가하는 경향을 보였으나, 평균체류시간은 감소하였다. 그러나 die hole 수가 증가할 수록, 측정한 4가지 system parameters는 모두 감소하는 경향을 나타내었다. 이러한 경향은 reverse element의 수를 증가시킨 스크류 조합을 사용한 경우에 더욱 뚜렸이 나타나는 결과를 보여 주었다. 이상의 결과를 각 스크류 조합에서 각각의 system parameters와 process parameters를 독립변수로 하는 함수식으로 나타낼 수 있었고, 이 때 각 함수식의 상관관계는 0.90 이상 이었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.186.1-186.1
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• 2011

Most of waste plastics including waste vinyls have been recycled up to about 50% of waste production, 4.5 million ton per year in 2009. To fundamentally increase the recycled amounts of waste plastics to waste production, the energy utilization of waste plastics is inevitable. But the contents of PVC included in waste plastics can limit the use as a RPF and make the air pollutants such as HCl and dioxin when it burns in the combustion system. Accordingly the source dechlorination by using heating method can be applied to make low contents of HCl as less than 0.6%. In this study the twin screw reactor using heat medium was used for the source dechlorination. As results of study, it was considered that this system is effective for the industrilal application.

• Food Science and Biotechnology
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• 제16권3호
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• pp.381-385
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• 2007

The objective of this experiment was to study the influence of feed moisture content on the degree of enzymatic hydrolysis of com starch in a twin screw extruder and the saccharification yield of the dried extrudate. The feed moisture content was set at 25, 30, and 35% and ${\alpha}$-amylase solution was directly injected into the feed section at a barrel temperature of $95^{\circ}C$ and screw speed of 250 rpm. Amyloglucosidase was used for the saccharification of the dried extrudate at a concentration of 0.055%(w/w). Expansion ratio and swelling factor of extrudates decreased with increasing the feed moisture content. Addition of ${\alpha}$-amylase during extrusion process raised reducing sugar content of extrudates which also increased with the feed moisture content. The saccharification yield of dried extrudate was higher for the extrudate with lower feed moisture content.

• Preventive Nutrition and Food Science
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• 제11권4호
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• pp.318-322
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• 2006

The objective of this experiment was to investigate the effect of extrusion of ginseng roots in twin screw extruder on susceptibility of ginseng starch toward hydrolysis by ${\alpha}-amylase$ BAN 480L (Novozyme, Denmark) and cellulase Celluclast 150L and saccharification by amyloglucosidase AMG-E (Novozyme, Denmark). The extrusion was conducted at 22% and 30% moisture contents of feed at screw speed 300 rpm. Barrel temperature at zone 1 was adjusted at $100^{\circ}C$ and $120^{\circ}C$. The results showed that extrusion process improved the ginseng ${\alpha}-amylase$ susceptibility as compared to traditionally dried ginseng (white and red ginseng). Reducing sugar of hydrolyzed extruded samples was 2,500% of its initial concentration, whereas the reducing sugar of hydrolyzed non-extruded sample was only 200% of its initial concentration. However, addition of cellulase during liquefaction lowered the saccharification yield of both non-extruded and extruded samples as well.

• 대한기계학회논문집A
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• 제29권1호
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• pp.145-155
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• 2005

In this study, a finite element method program code which can be accomodate boundary conditions on the complex surfaces has been developed to simulate polymer extruder processes. The analysis method includes the fractional 4-step method for efficient computation time and compact usage of memory storage to solve the velocities and the pressure values from the Navier-Stokes equation. By using the developed program which was verified with simple Poiseuille flow mixture phenomena in single-and twin-screw extruder are analyzed. It is concluded that the proposed method resulte Poiseuille Poiseuille d in fair agreement with the exact solution of simple flow and the back flow near the entrance happens in single-screw model. It is identified that the location and values of maximum pressure in the twin screw extruder model. It is expected that the Velocity field found can be used to predict the degree of mixture in the extruder barrel.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2005년도 하계 학술대회 논문집
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• pp.146-149
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• 2005

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2005년도 하계 학술대회 논문집
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• pp.154-157
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• 2005